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Roof Washing For Solar Panel Installation

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Freshly cleaned roof captured by our drone.

Published by: CA WASH PROS
Last Updated: 2025-12-05

California has installed the most solar in the second quarter of 2025. Solar investments continue to surge as more and more homeowners choose renewable energy.

One requirement for solar panel installation is roof washing. In this blog, we’ll explain why it’s required, what are roof cleaning methods, and who provides professional services.

Why Wash Your Roof Before Solar Installation

Solar companies inspect for moss and algae on your roof before you can qualify for installation. They require roof washing to ensure the safety of the technicians and to protect the roof area where the panels will be on.

Based on the solar layout, they would either ask for a sectional or full roof wash. Make sure to clarify with your solar inspector before you start looking for a roof cleaning company.

Comparing left side of the roof with moss and algae between right side without moss and algae.

For Safety Reasons

The moss and algae on your roof makes the surface slippery to walk and poses safety risks. If someone falls or gets hurt, both you and the solar company can be tangled up in a legal case.

Nobody wants anyone to get hurt. Additionally, it would be an inconvenience to get involved in a worst case scenario that could have been avoided in the first place.

For Roof Protection

They also want to protect your roof because the solar panels are going to shade underneath. The shaded areas are going to be an ideal environment for moss and algae growth.

Organic buildup can be harmful for your roof in the long run. It can deteriorate the roof material, cause water damage, retain moisture, and cause mold growth underneath. Roof washing removes pre-existing moss that can potentially spread out on the areas they installed on.

What Is Roof Washing?

Roof washing is the process of cleaning the roof to remove dirt and debris and eliminate moss, algae, mildew, lichen, and mold. There are different ways to clean a roof depending on its material.

Roof Cleaning Methods

  • Soft Wash: using very low and gentle water pressure (60 to 120 psi) and applying biocide treatment.
  • Pressure Wash: using high water pressure; roof pressure washing is an option only suitable for tile roofs because they are resilient and the surface is hard.
  • Manual Agitation and Biocide: using a stiff wood brush to scrub the moss and applying biocide treatment
Before and after of roof soft washing on a shingle roof.

Roof Cleaning Depending on Roof Type

Here’s a quick guide on how to clean different types of roofs.

  • Tile Roof: soft wash and pressure wash options
  • Shingle Roof: soft wash
  • Stone-coated Metal Roof: soft wash
  • Wood Shake Roof: manual agitation and biocide treatment

How Much Does A Roof Wash Service Cost?

In the Bay Area, a roof cleaning service on average-sized homes ranges from $750 to $200. The pricing depends on the size and scope of the project. Repairs may incur additional costs.

To get a free estimate, contact us at 408-800-3692 or fill up our quote form.

Before and after of a roof wash service.

Trusted Roof Cleaning Company in the Bay Area

If you’re dealing with a lot of moss and algae on your roof, your professional roof cleaner should be able to safely remove the moss and algae to satisfy solar requirements.

At CA Wash Pros, we offer expert roof washing services for homeowners who are preparing for solar panel installation. Whether you need a full roof cleaning or a sectional wash, we can guarantee the approval of your solar company.

Conclusion

Overall, roof washing is required before solar panel installation to ensure safety and protect the roof. If you’re looking for a roof cleaning company to get your home ready, you know where to start.

Frequently Asked Questions About Roof Washing

What types of roofs do you clean?
  • Tile roofs
  • Shingle roofs
  • Stone-coated metal roofs
  • Wood shake roofs

Typically, you’ll have to submit images of the cleaned roof and invoice as proof of work done. For specific guidelines, please contact your solar company.

It depends. The moss removal effects of roof washing can last up to 5 to 7 years.

In the Bay Area, if you’ve cleaned your roof after solar, you won’t have to worry about the moss because it grows at a slow rate in our climate. Naturally, there will be moss growth but not to the point that it’s going to cause damage from moisture retention.

There are other circumstances for roof washing. One is when you get a notice for non-renewal of your homeowners insurance policy because your roof is dirty. Another reason could be personal preference of wanting the roof to look good and brand new.

The more important thing after installation would be solar panel cleaning which we recommend at least once a year. For properties in busy industrial zones, more frequent cleanings should be done to maintain peak performance.

We are based in San Jose, CA and we serve many cities throughout the Bay Area. Click your city below and explore our services. We offer FREE online estimates.

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